Poly(vinyl butyral) (PVB) is commonly used in the manufacture of polymer sheets that can be used as interlayers in light-transmitting laminates such as safety glass or polymeric laminates. Safety glass often refers to a transparent laminate comprising a poly(vinyl butyral) sheet disposed between two sheets of glass. Safety glass often is used to provide a transparent barrier in architectural and automotive openings. Its main function is to absorb energy, such as that caused by a blow from an object, without allowing penetration through the opening or the dispersion of shards of glass, thus minimizing damage or injury to the objects or persons within an enclosed area.
Poly(vinyl butyral) is commonly produced using a conventional batch process that, like most batch processes, requires repeated cycles of reactant addition, mixing, emptying, and cleaning. One conventional method can require over a four hour batch cycle time.
While the production of poly(vinyl butyral) using a continuous method has been attempted, those conventional attempts have often produced less than satisfactory results, including, for example, resin having inconsistent poly(vinyl butyral) composition and processes that, due to mixer constraints, produce poly(vinyl butyral) containing undesirable agglomerations.
Accordingly, further improved methods are needed to produce poly(vinyl butyral) using a continuous process that is efficient, scalable, and that produces poly(vinyl butyral) of consistently high quality.